Public Vulnerability Reports

IBM AIX capture Terminal Control Sequence Buffer Overflow Vulnerability

07.26.07

BACKGROUND

The capture program is a setuid root application, installed by default under multiple versions of IBM AIX, that allows terminal sessions to be dumped to a file. More information can be found at the following URL.

http://publib.boulder.ibm.com/infocenter/pseries/v5r3/topic/com.ibm.aix.cmds/doc/aixcmds1/capture.htm

DESCRIPTION

Local exploitation of a stack-based buffer overflow vulnerability in the 'capture' program included with IBM Corp.'s AIX operating system allows an attacker to execute arbitrary code with root privileges.

The vulnerability exists within the code that parses terminal control sequences. A long series of control sequences will trigger an exploitable stack-based buffer overflow.

ANALYSIS

Exploitation of this vulnerability results in the execution of arbitrary code with root privileges.

The capture program is setuid root, and executable by any user with local access. The vulnerability is a stack-based buffer overflow, and is trivially exploitable.

DETECTION

iDefense has confirmed the existence of this vulnerability in AIX version 5.3 with service pack 6. Previous versions may also be affected.

WORKAROUND

Removing the setuid bit from the binary will prevent exploitation, but may make the program unusable by non-root users.

VENDOR RESPONSE

IBM Corp. has addressed this vulnerability by releasing interim fixes. More information can be found via the Bulletins tab of IBM's Subscription Service for UNIX and Linux servers. You can reach this service by clicking the URL shown below.

http://www14.software.ibm.com/webapp/set2/subscriptions/pqvcmjd?mode=1

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-3333 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems.

DISCLOSURE TIMELINE

06/05/2007 Initial vendor notification
06/08/2007 Initial vendor response
07/26/2007 Coordinated public disclosure

CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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LEGAL NOTICES

Copyright © 2007 Verisign, Inc.

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Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.